Ever thought about titanium Joe ? its non magnetic, doesn't corrode and the aerospace grade 6ALV barstock is pretty dimensionally constant with a surface finish which is quite good. Would be roughly a third of the cost of tungsten carbide.

trading hardness for a smoother surface is not a good trade in my opinion. The performance of the arm design with a Pyrex tube is already above just about any arm money can buy. It is the hard glass which provides the improved performance due to the low friction. If you are looking to run in the tube I suppose that you could hone the tube without much trouble if you really wanted to. Flat window glass could be lapped one piece on another to a precision surface without a lot of trouble. In this way a very fine open bottom "V" could be made and you could experiment with any angle you like with steeper being better IMO. This could just as easily be flipped over and you could run on the outside. A tube is not necessary. Hope this is of interest. Best regards Moray James.

I am sure you could use titanium without hurting the design. But why settle for a Yugo when you can have a Mercedes. Both will drive you from point A to point B ( at least most of the time ha,ha). You could probably use hard anodized precision aluminum tubing. To do a proper job imho using titanium or aluminum you would have to machine/grind/polish to make sure it is straight with a nice finish. The carbide rod I have now is precision ground and polished within .0005 with a mirror finish. No need to look any further for me.

Life is short, I am not going to "cheap" out for a couple of dollars in materials. I figure it may cost me $200 or so in materials but this arm should rival the performance of tonearms that cost thousands. Still a bargain in my book. I realize this just a passing experiment for some folks here and that is fine. Not everyone can spend lots of money on a project like this. I am in the process of finishing off a 4 way horn system and home theater room so when The time come I will give this arm a serious try.

Moray - the amateur telescope making guys can actually lap glass to accuracies which are measured in fractions of the wavelength of light, so I'm sure there is a lot of merit in your suggestion.

Siddley,
Last night I set up some 9" ground steel parallels on a surface plate and positioned a dial indicator to measure for out of round, bow and any irregularities which could show up. Rolling the 10mm glass tube on the surface plate did show up the out of roundness and that measured no more than .002 inches. The same was true for bow over the 9" length. All deviations were smooth and gradual. IMO it will be impossible to hear any effect on musik playback.

Friction is something which I feel is thrown around with reckless abandon and really it shows a great lack of knowledge. My own lack of knowledge
included. So I took a good look at the Wikipedia entries. May I suggest that all the folks involved in this project spend some time learning about friction and all its types. Very enlightening and a better understanding of the subject will answer a lot of questions and clear up some misunderstandings.

Siddley,
Last night I set up some 9" ground steel parallels on a surface plate and positioned a dial indicator to measure for out of round, bow and any irregularities which could show up. Rolling the 10mm glass tube on the surface plate did show up the out of roundness and that measured no more than .002 inches. The same was true for bow over the 9" length. All deviations were smooth and gradual. IMO it will be impossible to hear any effect on musik playback.

BillG

Great stuff, no arguing with that. I think I'll return to just lurking on this thread for now because I'm not sure I'm helping
much.

In this design we can break it down into 3 parts, rolling.resistance in the horizontal plane, static friction in the vertical while setting tracking pressure and the vertical friction in use which will be lower than the static friction .

I am sure you could use titanium without hurting the design. But why settle for a Yugo when you can have a Mercedes. Both will drive you from point A to point B ( at least most of the time ha,ha). You could probably use hard anodized precision aluminum tubing. To do a proper job imho using titanium or aluminum you would have to machine/grind/polish to make sure it is straight with a nice finish. The carbide rod I have now is precision ground and polished within .0005 with a mirror finish. No need to look any further for me.

Life is short, I am not going to "cheap" out for a couple of dollars in materials. I figure it may cost me $200 or so in materials but this arm should rival the performance of tonearms that cost thousands. Still a bargain in my book. I realize this just a passing experiment for some folks here and that is fine. Not everyone can spend lots of money on a project like this. I am in the process of finishing off a 4 way horn system and home theater room so when The time come I will give this arm a serious try.

Joe

The real question is will what you are doing make any REAL measurable difference in the sound that you can actually perceive? If that floats your boat, go for it.

Wow that is good news, that glass tubing is definitely good for this project. I cut some 17mm pyrex test tubes I had and found a .002 to ,003 run out which would also be good. I guess it depends on who makes the glass and where it comes from. It is a good idea to check or have checked the tubing you are going to use.

In this design we can break it down into 3 parts, rolling.resistance in the horizontal plane, static friction in the vertical while setting tracking pressure and the vertical friction in use which will be lower than the static friction .

If your system is hi-rez enough you can tell the difference between tonearms fairly easily. In this particular case I have not built this arm yet so I can not say.

What I can say is I can hear the difference between copper wound output transformers and silver wound transformers. The differences between various 45, 2a3, 300b output tubes is also pretty easy to hear. The main question is if what you are hearing is actually better or just different---which maybe totally subjective. Most of the times the differences are subtle and sometimes they are not. For 80 percent of the people the differences don't mean a thing. Most young people today are happy with the sound of their I-Pod and that is fine with me. I will stick with my 4 way horn system using a mix Tad and field coil drivers. That floats my boat !!!!